The subject invention is directed toward the valve art and, more particularly, to the improved diaphragm-type valve.
Metal diaphragm valves are often used in systems handling toxic and dangerous fluids. The valves are preferred in such environments because the diaphragm can provide total hermetic sealing between the valve cavity and the valve operating mechanism.
As is apparent, the diaphragm is a very critical element in such valves since failure of the diaphragm can result in sudden escape of the dangerous fluids. It is generally recognized that the life of the diaphragm element is closely related to the types of stresses to which it is subjected during operation. Consequently, attempts have been made to improve not only the diaphragm element but, also, the manner in which it is mounted and actuated. Generally these attempts have significantly increased the complexity of the valves and/or the problems associated with their manufacture and maintenance.
The subject invention provides a diaphragm-type valve which includes a unique diaphragm construction and mounting arrangement which prevents the diaphragm from being subjected to any undesirable stresses and provides extremely long diaphragm life.
The invention also provides an improved operating mechanism which allows the diaphragm and the associated valve element to be moved between the open and closed positions without subjecting the diaphragm to torsional loads or the like. In addition, the operating mechanism provides a readily visual indication of the valve operating position.
The invention further concerns an improved valve stem tip assembly which is particularly suited for use in diaphragm valves as well as other types of shut-off valves.